The Orange Chef’s Claire McClendon, left, and Amy Wu lead lunch prep at the company’s San Francisco offices. Photo: Jim Merithew/Cult of Mac

SAN FRANCISCO — James Armstrong might be one of the few iOS engineers who loses weight while on a coding bender.

Armstrong is lead developer at The Orange Chef Co., the company behind a smart kitchen scale called Prep Pad. It weighs your food and, based on the nutritional profile you set, gives you a more accurate idea of how much you should eat. While working on a companion iPad app called Countertop, Armstrong beta tested his meals and realized how super-sized they were. So he cut the portions and shed 30 pounds.

“I had to buy new clothes twice,” he says.”I bought a bunch of clothes, then I had to buy ‘em again — it’s made that much difference.”